Oxygen tension (PO2) was measured in rabbit whisker barrel cortex using oxygen sensitive electrodes to investigate the impact of isoflurane anesthesia on oxygen autoregulation. Responses to 90s episodes of 100% oxygen inspiration were obtained from rabbits before anesthesia, and then when the animals were anesthetized with 0.5% or 1.5% isoflurane. For each episode, ΔPO2 (i.e., hyperoxic PO2 minus baseline PO2) was computed. Compared to the conscious state, brain ΔPO2 increased during anesthesia with 1.5% isoflurane (0.73 MAC) by an average of 116%, whereas 0.5% isoflurane produced an insignificant average increase of 31%. The results suggest that moderate levels of isoflurane impaired autoregulation of brain tissue oxygen tension.
- Barrel cortex
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